Map Grids on Topo Maps: Latitude, Longitude, UTM & State Plane October 9, 2026The numbers and tick marks around the edge of a topo map are coordinate systems. Here's how to read latitude and longitude, the UTM grid, and State Plane ticks, and...
Contour Lines on Topo Maps: Index, Intermediate & Depression Contours October 9, 2026The brown lines are what make a topo map topographic. Here's how to read every USGS contour symbol, from index contours and depressions to glaciers and underwater depth contours.
Coastal Symbols on Topo Maps: Shorelines, Reefs, Rocks & Wrecks October 9, 2026Where land meets water, USGS maps borrow symbols from nautical charts: rocks awash, reefs, wrecks, and depth curves. Here's how to read every coastal and bathymetric symbol.
Building, Campground & Landmark Symbols on Topo Maps October 9, 2026Black squares, flags, crosses, and tents: here's what every building, campground, and landmark symbol on a USGS topo map means.
Boundary Lines on Topo Maps: States, Counties, Parks & Public Land October 9, 2026Boundary lines on a topo map are black dash patterns, and parks and public lands get a colored band along the inside. Here's how to tell them apart.
Benchmarks & Spot Elevations: What BM Means on a Topo Map October 9, 2026Those little Xs, triangles, and BM labels are survey points with precisely measured positions and elevations. Here's how to read every USGS control and monument symbol.
